Nano Science and Technology Program, Department of Chemistry, Institute of Molecular Functional Materials, The Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon, Hong Kong, China.
Anal Chem. 2010 Aug 15;82(16):7035-43. doi: 10.1021/ac1018028.
Human serum albumin (HSA) is a major protein component of blood plasma, and its assay is of obvious value to biological research. We, herein, present a readily accessible fluorescent bioprobe for HSA detection and quantitation. A nonemissive tetraphenylethene derivative named sodium 1,2-bis[4-(3-sulfonatopropoxyl)phenyl]-1,2-diphenylethene (BSPOTPE) is induced to emit by HSA, showing a novel phenomenon of aggregation-induced emission (AIE). The AIE bioprobe enjoys a broad working range (0-100 nM), a low detection limit (down to 1 nM), and a superior selectivity to albumins. The fluorescent bioassay is unperturbed by the miscellaneous bioelectrolytes in the artificial urine. The AIE luminogen can also be used as a rapid and sensitive protein stain in gel electrophoresis for HSA visualization. Utilizing the AIE feature of BSPOTPE and the Forster resonance energy transfer from HSA to BSPOTPE, the unfolding process of HSA induced by guanidine hydrochloride is monitored, which reveals a multistep transition with the involvement of molten globule intermediates. Computational modeling suggests that the AIE luminogens dock in the hydrophobic cleft between subdomains IIA and IIIA of HSA with the aid of hydrophobic effect, charge neutralization, and hydrogen bonding interactions, offering mechanistic insight into the microenvironment inside the hydrophobic cavity.
人血清白蛋白（HSA）是血浆中的主要蛋白质成分，其测定对生物研究具有明显的价值。我们在此提出了一种易于获得的荧光生物探针，用于 HSA 的检测和定量。一种非发光的四苯乙烯衍生物，命名为[1,2-双[4-（3-磺丙氧基）苯基]-1,2-二苯基]乙烯钠（BSPOTPE），被 HSA 诱导发射，显示出聚集诱导发射（AIE）的新现象。AIE 生物探针具有较宽的工作范围（0-100 nM）、较低的检测限（低至 1 nM）和对白蛋白的优异选择性。荧光生物测定不受人工尿液中各种生物电解质的干扰。该 AIE 发光体也可用作凝胶电泳中 HSA 可视化的快速灵敏蛋白质染色剂。利用 BSPOTPE 的 AIE 特性和 HSA 向 BSPOTPE 的Förster 共振能量转移，监测盐酸胍诱导的 HSA 展开过程，揭示了涉及无规卷曲中间体的多步转变。计算建模表明，AIE 发光体在疏水作用、电荷中和和氢键相互作用的帮助下，在 HSA 的亚域 IIA 和 IIIA 之间的疏水裂缝中结合，为疏水腔内部的微环境提供了机理见解。
